Evaluation of a new insecticide formulation ( F 2 ) as a protectant of stored wheat , maize , and rice $

A new commercial formulation, F2, was evaluated as a protectant of stored wheat, stored maize, and stored rough (paddy) rice. This formulation comprises the technical active ingredients 0.03% deltamethrin, 0.37% piperonyl butoxide, and 0.95% chlorpyriphos-methyl, plus 10% mineral oil and 88.0% of the diatomaceous earth Protect-It. Tests were conducted with dust and slurry formulations at 50 and 100 ppm, 57% and 75% relative humidity, and 22 C, 27 C, and 32 C. On wheat, survival of the lesser grain borer, Rhyzopertha dominica (F.), ranged from 0% to 30.0%, survival of the rice weevil, Sitophilus oryzae (L.), was 0–6.2%, and survival of the red flour beetle, Tribolium castaneum (Herbst), was 0–97.5%. Few F1 adults of any of the three species were found in the treated samples. Survival of the maize weevil, Sitophilus zeamais (Motschulsky), on treated corn was 0–32.5%, while survival of T. castaneum was 0–88.7% in the 50-ppm dust and slurry treatments, and 0–51.4% in the 100-ppm treatments. Again, few F1 adults of either species were found in treated maize. Survival of R. dominica on treated rough rice averaged 0–4.1% and survival of S. oryzae on treated rice was 0–48.8%, but the majority of weevils that survived were in one replicate. F1 adults in the treatments ranged from 0 to 24.4. Results show that the combination insecticidal product F2 was extremely effective on all three commodities at the rate of 100 ppm, as either a dust or slurry, and could be used as a commodity protectant. Published by Elsevier Science Ltd.